This invention relates to cosmetic creams containing granular components, useful for cleansing and scrubbing the skin. It particularly relates to such creams which contain granules of a salt, in particular sodium or potassium chloride and which are stable under storage and use conditions. It further relates to such creams that are soluble in water and do not require mechanical removal after use.
Cosmetic creams which contain solid particulate components are known in the art. The presence of the solid particles renders them useful for scrubbing and cleansing the skin, particularly of the face. Certain creams of such a kind contain polyethylene spherules, which are inert and insoluble and must removed from the user""s skin, after application of the cream, by sufficiently intensive rinsing. Other creams, also known in the art, contain sodium chloride granules. They do not require such intensive rinsing, but have the drawback that the granules tend to dissolve in the water phase, and disappear during the storage of the cream and in the period of their use, so that the cream loses the desired properties. Further, such creams do not have a water phase, and are heavy on spreading on the skin. Still further, their preparation is not an easy process, because the addition of salts to creams, which generally comprise more than 50% of water, generates an aqueous solution of the salt, which is difficult to emulsify with the oily cream bases and often affects the physical properties of the resulting emulsion in an undesirable manner. In general, the complex nature of these emulsions of an aqueous and a non-aqueous phase creates manufacturing problems and deterioration of the properties of the resulting product, which the art has so far been unable to overcome.
It is therefore a purpose of this invention to provide a cosmetic cream which comprises salt granules and which is stable in storage and in use and does not lose its properties, and is therefore adapted for scrubbing, massaging and cleansing the skin.
It is another purpose of this invention to provide such a cosmetic cream which contains salt granules which will not dissolve and disappear with storage.
It is a further purpose of this invention to provide such a cosmetic cream which does not require rinsing, or at least not an immediate rinsing, after application.
It is a still further purpose of this invention to provide a cosmetic cream the use of which produces a particularly pleasant feeling.
It is still further purpose of this invention to provide such a cosmetic cream which contains granules of potassium salts.
It is a still further purpose of this invention to provide such a cosmetic cream which contains a plurality, up to even all, of the minerals of the Dead Sea.
It is a still further purpose of this invention to provide such a cosmetic cream which contains mixtures of granules of different salts.
It is a still farther purpose of this invention to provide such a cream which is easy to spread on the skin and has all the physical properties required for this purpose.
It is a still further purpose of this invention to provide a method of making a cosmetic cream, containing salt granules, for scrubbing and cleansing the skin, which method permits to impart to the cream the desired physical properties.
It is a still further purpose of this invention to provide such a method which permits to disperse in the cream salt granules that are stable and are not affected by storage of the cream.
It is a still further object of this invention to provide such a method which permits to prepare cosmetic creams containing granules of water-soluble salts other than sodium chloride.
It is a still further object of the invention to provide scrubbing creams in which the salt granules substantially completely dissolve after application, as a result of the scrubbing action, so that, after use, practically no granules are left on the skin and no rinsing, at least no immediate rinsing, is required and penetration of the salts into the skin is enhanced.
Other purposes and advantages of the invention will appear as the description proceeds.
The cosmetic cream according to the invention is characterized in that it contains at least a solid salt in the form of granules and an aqueous solution containing at least the same salt in such an amount as to become saturated with respect to said salt at a temperature not lower than room temperature.
In an embodiment of the invention, said solution becomes saturated with respect to said salt at a temperature higher than room temperature and preferably not lower than about 40xc2x0 C.
In another embodiment of the invention, said solution becomes saturated with respect to said salt at or about room temperature, and preferably at a temperature of about 25xc2x0 C.
The word xe2x80x9csaltxe2x80x9d is used in this specification and claims in its broad chemical meaning, and not as a common word to designate sodium chloride. The word xe2x80x9cgranulesxe2x80x9d means small solid particles and does not imply any limitation as to the shape of such particles nor as to their structure, though salt granules will generally have a crystalline structure.
In an embodiment of the invention, the aqueous solution contains a single salt as the sole minerals solute. In another embodiment, it contains a combination of Dead Sea salts as minerals solute.
In a preferred form of the invention, the salt granules are in an amount comprised between 3 and 15% and preferably between 5 and 10 % of the total cream All the percentages in this specification and claims are by weight, unless otherwise specified.
Preferably, the maximum linear dimension of the salt granules is 0.1-0.3 mm.
The salt is preferably sodium chloride or potassium chloride.
In a form of the invention, the cream also contains mixtures of mineral salts, particularly a mixture sold by Dead Sea Works Ltd. under the trade name DHB 400. A typical analysis of the aforesaid DHB 400 mixture is shown in Table I below.
The cosmetic scrub creams in this invention refers are emulsions of an aqueous phase and an oily phase to which the solid salt is added. The oily phase plus the aqueous phase, plus the additives, fragrance and preservatives, other than the solid salt, will be called hereinafter xe2x80x9cthe cream basexe2x80x9d. The conventional prior art cosmetic creams, without added salt, are therefore basically emulsions of the cream base of this invention and water. The cosmetic creams of this invention contain water preferably in an amount of at least about 30% of the cream base or of the total of water and the cream base.
Therefore they contain 5 to 40 parts of salt, partly as granules and partly dissolved, 40 to 60 parts of cream base, and 30 to 50 parts of water. All parts in this specification and claims are by weight.
The process for preparing a cosmetic cream according to the invention comprises, in any suitable order, the steps of:
1xe2x80x94mixing a solution containing at least a salt in the amount-contained by a solution that is saturated at a first temperature not lower and preferably higher than room temperature, with the water soluble ingredients of the cream base;
2xe2x80x94emulsifying said solution with the components of the oily phase of the cream base at a second temperature, higher than said first temperature, to obtain a complete mixture;
3xe2x80x94homogenizing the two phases and concurrently cooling the complete mixture;
4xe2x80x94when a third temperature higher than room temperature has been reached, adding the DHB solution to the mixture, while continuing to homogenize said mixture, until room temperature is reached;
5xe2x80x94adding fragrances and preservatives;
6xe2x80x94mixing additives; and
7xe2x80x94adding solid salt particles while continuing to homogenize said mixture.
Of course, some steps, e.g. steps 5 and 6, can be unified into a single step, as will be apparent to the skilled person.
The salt or salts, to the solution of which step 1 of the process refers, and which is added as a solid in step 7, is the salt or salts which is to be contained in the form of granules on the cosmetic cream. The additives, that may be optionally added, can be chosen by skilled persons as desired for any particular cosmetic formulation. Examples are given hereinafter.
xe2x80x9cRoom temperaturexe2x80x9d means herein the temperature at which the cream is expected to be used, and, at any rate, a temperature comprised between 18xc2x0 and 32xc2x0 C. A typical room temperature is 25xc2x0 C. Said first temperature is preferably higher than room temperature by 10xc2x0-20xc2x0 C., typically by 15xc2x0 C. Said second temperature is considerably higher than said first temperature, e.g. is 75-80xc2x0 C. Said third temperature is preferably higher than room temperature by 10-20xc2x0 C., typically by 15xc2x0 C. It should be understood that said solution may be prepared at said first temperature or at a higher temperature.
In a preferred manner of carrying out step 1 of the process, the salt solution is mixed firstly with the water-soluble components of the cream base to obtain a first partial e. The oily componentsxe2x80x94xe2x80x9coilyxe2x80x9d meaning herein xe2x80x9cliquid or solid and not mixable with waterxe2x80x9dxe2x80x94of the cream base are separately mixed to obtain a second partial mixture. Then said first and second partial mixtures, plus the additives, fragrance and preservatives, are mixed together to form what will be called herein xe2x80x9cthe complete mixturexe2x80x9d. Preferably, all these mixing operations are carried out at the temperatures specified hereinbefore.
In a preferred manner of carrying out step 7 of the process, the solid salt granules are slowly added to the complete mixture and, during said addition, the homogenization operation is continued under milder mechanical conditions, e.g. at a reduced speed of rotation if a rotary mixer is used, until a satisfactory homogeneity has been achieved.
In a preferred embodiment of the invention, a liquid mixture of salts, e.g. the aforesaid DHB 400 mixture, is added in step 4 of the process to the complete mixture, before adding the salt in granule form.